Silicon and Silicon production

SILICON

Silicon is the second most common chemical element with a share of 25% in the earth crust after oxygen. It is mostly found as silicates or oxides in different minerals like quartz, feldspar or mica. Elementary silicon is very rare in nature.

The most important raw material for silicon metal production is very pure quartz, either in form of gravel or quartzite. 

According to his chemical formula pure quartz has about 47% of silicon, of which about 80% can be recovered in an industrial process. Large scale production of silicon is done by reduction of quartz with carbon. The necessary high temperatures of about 2000 °C are processed by an electric arc in a reduction furnace.

SILICON PRODUCTION

A mixture of quartz and different carbon materials (coal, coke or charcoal) is continuously fed into the furnace. From the furnace tap hole liquid silicon is extracted with a temperature of about 1600°C. The metal is further processed by oxidative refining, casting, crystallization and crushing.

The purity of metallurgical silicon is about 99%. Typical impurities that come from the raw materials are iron, aluminum, calcium and titanium.